Iniquitous - Sanguine Blood Seekers, #3

Kamose, undead before he was pharaoh, has lived on fringes of the vampire realm for thousands of years. He feels no kinship to the bloody bastards. Against vampire laws, Kam kills his master, the only man who loved him. He pays for that atrocity every day. Allowing Kam's sarcophagus to be desecrated and tossed into a pile of trash as if he were truly dead, even God deserts Kamose. Until Matthias, the thirteenth apostle, crosses his path. Saint Matthias should have been one of the twelve apostles.
Instead, he gains the position after Jesus' death. By then he's a monster subsisting on human blood. Every bite, every draw of sustenance fills him with guilt he can't assuage. The only time he experiences peace is in the arms of a much older creature. A vampire so vile and sacrilegious, Matthias fears he'll cause both their souls to burn in Hell!